The team announced the move Friday night, a day after Mike Pettine left Buffalo to take over as the Cleveland Browns’ head coach. Schwartz was fired Dec. 30, a day after the Lions missed the playoffs with a 7-9 record.

In four seasons in Detroit, the 47-year-old Schwartz was 29-51. That included a 10-6 finish in 2011 when the Lions reached the playoffs for the first time in 12 years.

Schwartz has 21 years of NFL coaching experience, including nine as a defensive coordinator.

The Bills also reached a deal to hire one of Schwartz’s former assistants, Todd Downing, to become quarterbacks coach.